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Northeast Temperate Network (NETN)

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Maine Maritime Academy undergraduate student interns Amanda Andrews and Lauren Grotton sample vegetation in Acadia National Park's Bass Harbor Marsh.
Maine Maritime Academy undergraduate student interns Amanda Andrews and Lauren Grotton sample vegetation in Acadia National Park's Bass Harbor Marsh. Ann Cleveland photo.

NETN identified the biological integrity of intertidal marsh habitats as a high priority vital sign for Acadia National Park, Boston Harbor Islands National Recreation Area, and Saugus Ironworks Iron Works National Historic Site. The protocols will be closely based on the Northeast Coastal and Barrier Network's monitoring programs and will provide details on the development and implementation of a robust and rigorous tidal marsh vegetation monitoring program for marshes of management interest in these parks. Salt marsh vegetation species diversity and percent cover will be measured on a 3-year repeating sampling cycle looking for changes in indivudual salt marsh community structure over time.

As sea-level rises and organic substrates subside, the height of salt marsh surfaces must increase to keep pace. If the sedimentation rates in a salt marsh do not equal or exceed the net loss in elevation due to the steady increase in sea level and salt marsh subsidence, it will "drown". When a salt marsh "drowns", the surface of the marsh becomes sub-tidal which can cause drastic habitat changes such as the conversion of vegetated salt marsh to unvegetated mud flat.

Understanding changes in relative salt marsh elevation is important for interpreting changes in salt marsh vegetation communities. This project is also part of a worldwide effort to monitor sea level rise with sediment erosion tables (SETs) and cryogenic coring devices.

Salt marshes, particularly in the U.S. northeast, serve as critical habitat for forage species which in turn provide an important food resource for other adult fish species and coastal bird populations. Salt marsh ecosystems perform a variety of ecologically important chemical functions including organic and inorganic waste retention, transformation and removal; a significant role in global carbon, nitrogen, and sulfur biogeochemical cycling (with important ramifications to climate change and coastal eutrophication); sediment entrapment; and buffering of uplands from storm and wave impacts, erosion, and coastal flooding.

Nutrient enrichment of the coastal zone is a worldwide consequence of human population growth. The population density of Northeast coastal fringe is more than double that of any other region of the country, and it continues to grow. The consequent residential, agricultural, and urban expansion will result in a continued increase in anthropogenic nutrient loading to the region's coastal zone. Estuaries can generally assimilate some degree of enrichment without major ecological ramifications, but excessive nutrient inputs typically lead to dense blooms of phytoplankton and fast-growing macroalgae, loss of seagrasses, and decreased oxygen availability in sediments and bottom waters. Cascading effects may include changes in the species composition and abundance of invertebrates, decline in fish and wildlife habitat value, and the collapse of commercially harvestable fin- and shellfish stocks.


NETN Salt Marsh Monitoring Materials

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NETN Salt Marsh Vegetation and SET Monitoring Sites




Northeast Temperate Network Staff Contacts for Freshwater Wetland Monitoring

Name Title/Position Phone Number Email Address
Aaron Weed Program Manager 802-457-3368
ex. 237
aaron_weed@nps.gov
Kate Miller Plant Ecologist 207-288-8736 kathryn_miller@nps.gov
Ed Sharron Science Communication Specialist 802-457-3368 ex 223 ed_sharron@nps.gov
Adam Kozlowski Data Manager 802-457-3368 ex 240 adam_kozlowski@nps.gov
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